Windows XP has a built in Users Accounts tool in the Control Panel. But a more advanced tool which is usually invoked from a command (control userpasswords2) can be added to the Control Panel. This tool when opened looks like this :
To do so, you can download the following file, unzip them to a folder.
Double-click on add_uuserpassword2.reg to add the tool to your Control Panel. When asked click on Yes. It would look in the Control Panel as shown in the picture below:
If later for some reason, you might want to remove this tool from Control Panel, you can double-click on rem_userpasswords2.reg. Again, when asked for confirmation, choose Yes.